Rotary fluid machinery

ABSTRACT

A rotary fluid machine is provided that includes a rotor chamber ( 14 ), a rotor ( 41 ) housed within the rotor chamber ( 14 ), vanes ( 48 ) guided by vane channels formed in the rotor ( 41 ), and pistons ( 47 ) slidably fitted in cylinders ( 44 ) provided in the rotor ( 41 ). High temperature water of a hydrostatic bearing supporting the vane ( 48 ) in the vane channel in a floating state is retained by a plurality of pockets ( 48   f ) recessed in the surface of the vane ( 48 ), and the high temperature water retained by the pockets ( 48   f ) is supplied to the rotor chamber ( 14 ) during an expansion stroke as a result of radially outward movement of the vane ( 48 ) accompanying rotation of the rotor ( 41 ). The high temperature water supplied to the rotor chamber ( 14 ) is gasified into steam, and the pressure energy thereof improves the performance of the rotary fluid machine.

FIELD OF THE INVENTION

The present invention relates to a rotary fluid machine forinterconverting the pressure energy of a gas-phase working medium andthe rotational energy of a rotor.

BACKGROUND ART

A rotary fluid machine disclosed in Japanese Patent ApplicationLaid-open No. 2000-320543 is equipped with a vane piston unit in which avane and a piston are combined; the piston, which is slidably fitted ina cylinder provided radially in a rotor, interconverts the pressureenergy of a gas-phase working medium and the rotational energy of therotor via a power conversion device comprising an annular channel and aroller, and the vane, which is radially and slidably supported in therotor, interconverts the pressure energy of the gas-phase working mediumand the rotational energy of the rotor.

The vane of such a rotary fluid machine is slidably supported in a vanechannel formed radially in the rotor, and by supplying a high pressureliquid-phase working medium to sliding surfaces thereof so as to form ahydrostatic bearing, the vane is floatingly supported, thus greatlyreducing the sliding resistance. When the liquid-phase working mediumsupplied to the hydrostatic bearing has a relatively high temperatureand sufficient thermal energy, if its thermal energy can be utilizedeffectively without being wastefully disposed of, the performance of therotary fluid machine can be still further improved.

DISCLOSURE OF THE INVENTION

The present invention has been accomplished under the above-mentionedcircumstances, and an object thereof is to improve the performance of arotary fluid machine by utilizing effectively the thermal energy of aliquid-phase working medium for a hydrostatic bearing, the liquid-phaseworking medium being supplied between a vane and a vane channel.

In order to achieve the above object, in accordance with a first aspectof the present invention, there is proposed a rotary fluid machine thatincludes a rotor chamber formed in a casing, a rotor rotatably housedwithin the rotor chamber, a plurality of vane channels formed radiallyin the rotor, and a plurality of vanes slidably supported in therespective vane channels, the vanes being supported in a floating stateby a hydrostatic bearing formed by supplying a liquid-phase workingmedium to sliding surfaces of the vane channels and the vanes, and therotary fluid machine interconverting the rotational energy of the rotorand the pressure energy of a gas-phase working medium supplied to vanechambers defined by the rotor, the casing, and the vanes, whereinliquid-phase working medium guide means for introducing into the vanechambers the liquid-phase working medium for the hydrostatic bearing isprovided on sliding surfaces of the vanes, and the temperature and thepressure of the liquid-phase working medium that is introduced into thevane chambers by the liquid-phase working medium guide means are set sothat the liquid-phase working medium can gasify into the gas-phaseworking medium in the vane chambers.

In accordance with this arrangement, since the liquid-phase workingmedium for the hydrostatic bearing for supporting the vane in a floatingstate in the vane channel is introduced into the vane chamber by theliquid-phase working medium guide means provided on the sliding surfaceof the vane, and the temperature and the pressure of the liquid-phaseworking medium that is introduced into the vane chamber are set so thatit can gasify in the vane chamber, the performance of the rotary fluidmachine can be improved by utilizing effectively the pressure energy ofthe gas-phase working medium that is gasified in the vane chamber.

Furthermore, in accordance with a second aspect of the presentinvention, in addition to the first aspect, there is proposed a rotaryfluid machine wherein the liquid-phase working medium guide meanscomprises a pocket that is recessed in the sliding surface of the vaneso that it can retain the liquid-phase working medium, and when thepocket communicates with the vane chamber as a result of radiallyoutward movement of the vane accompanying rotation of the rotor, theliquid-phase working medium, which has a higher pressure than theinternal pressure of the vane chamber, is introduced into the vanechamber.

In accordance with this arrangement, since the liquid-phase workingmedium guide means comprises the pocket that is recessed in the slidingsurface of the vane so that it can retain the liquid-phase workingmedium, when the pocket communicates with the vane chamber as a resultof radially outward movement of the vane accompanying rotation of therotor, the high pressure liquid-phase working medium retained in thepocket can be introduced into the vane chamber. Therefore, byappropriately setting the radial position of the pocket, the timing withwhich the pocket communicates with the vane chamber can be freelyadjusted, and by making the internal pressure of the pocket higher thanthe internal pressure of the vane chamber at the moment ofcommunication, the liquid-phase working medium can be reliably suppliedto the vane chamber.

Moreover, in accordance with a third aspect of the present invention, inaddition to the first or second aspect, there is proposed a rotary fluidmachine wherein the liquid-phase working medium for the hydrostaticbearing is preheated so that it gasifies when introduced into the vanechamber.

In accordance with this arrangement, by preheating the liquid-phaseworking medium for the hydrostatic bearing, the liquid-phase workingmedium can be reliably gasified when it is introduced into the vanechamber.

Furthermore, in accordance with a fourth aspect of the presentinvention, in addition to the third aspect, there is proposed a rotaryfluid machine wherein the liquid-phase working medium for thehydrostatic bearing is preheated by utilizing the waste heat of aninternal combustion engine.

In accordance with this arrangement, since the liquid-phase workingmedium for the hydrostatic bearing is preheated by utilizing the wasteheat of the internal combustion engine, it is unnecessary to employ aspecial heat source, thus contributing to a reduction in fuelconsumption.

A pocket 48 f and a slit 48 g of embodiments correspond to theliquid-phase working medium guide means of the present invention, andsteam and water of the embodiments correspond to the gas-phase workingmedium and the liquid-phase working medium respectively of the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 to FIG. 16 illustrate a first embodiment of the presentinvention;

FIG. 1 is a schematic view of a waste heat recovery system of aninternal combustion engine;

FIG. 2 is a longitudinal sectional view of an expander, corresponding asectional view along line 2-2 of FIG. 4;

FIG. 3 is an enlarged sectional view around the axis of FIG. 2;

FIG. 4 is a sectional view along line 4-4 of FIG. 2;

FIG. 5 is a sectional view along line 5-5 of FIG. 2;

FIG. 6 is a sectional view along line 6-6 of FIG. 2;

FIG. 7 is a sectional view along line 7-7 of FIG. 5;

FIG. 8 is a sectional view along line 8-8 of FIG. 5;

FIG. 9 is a sectional view along line 9-9 of FIG. 8;

FIG. 10 is a sectional view along line 10-10 of FIG. 3;

FIG. 11 is an exploded perspective view of a rotor;

FIG. 12 is an exploded perspective view of a lubricating waterdistribution section of the rotor;

FIG. 13 is a schematic view showing cross-sectional shapes of a rotorchamber and the rotor;

FIG. 14 is a graph showing the relationship between the amount ofincrease in output of the expander and the phase at which lubricatingwater is supplied during an expansion stroke of the expander, fordifferent temperatures of the lubricating water;

FIG. 15 is a graph showing the relationship between the amount ofincrease in output of the expander and the phase at which lubricatingwater is supplied during the expansion stroke of the expander, fordifferent amounts of lubricating water supplied;

FIG. 16 is a view, corresponding to FIG. 7, for explaining theoperation.

FIG. 17 is a view, corresponding to FIG. 7, of a second embodiment.

FIG. 18 is a view, corresponding to FIG. 7, of a third embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

A first embodiment of the present invention is explained below withreference to FIG. 1 to FIG. 16.

As shown in FIG. 1, a waste heat recovery system 2 for recoveringthermal energy of exhaust gas of an internal combustion engine 1 andoutputting mechanical energy includes an evaporator 3 that heats waterusing the exhaust gas of the internal combustion engine 1 as a heatsource so as to generate high temperature, high pressure steam, anexpander 4 that outputs axial torque as a result of expansion of thehigh temperature, high pressure steam, a condenser 5 that cools andliquefies decreased temperature, decreased pressure steam dischargedfrom the expander 4, a tank 6 that holds water discharged from thecondenser 5, and a low pressure pump 7 and a high pressure pump 8 thatresupply water within the tank 6 to the evaporator 3.

Water within the tank 6 is pressurized to 2 to 3 MPa by the low pressurepump 7 disposed in a passage P1, passes through a heat exchanger 102provided in an exhaust pipe 101 of the internal combustion engine 1, andis thus preheated. Water thus preheated by passing through the heatexchanger 102 is supplied to a water jacket 105 formed within a cylinderblock 103 and a cylinder head 104 of the internal combustion engine 1via a passage P2, cools a heated section of the internal combustionengine 1 while passing through the water jacket 105, and is itselffurther heated by carrying away the heat of the heated section. Waterdischarged from the water jacket 105 is supplied to a distribution valve106 via a passage P3, and distributed to a first line connected to apassage P4, a second line connected to a passage P5, a third lineconnected to a passage P6, and a fourth line connected to a passage P7.

Water distributed to the first line formed from the passage P4 in thedistribution valve 106 is pressurized to a high pressure of 10 MPa orhigher by the high pressure pump 8, is supplied to the evaporator 3,becomes high temperature, high pressure steam as a result of heatexchange with high temperature exhaust gas, and is supplied to a highpressure section (cylinders 44 of the expander 4, which will bedescribed later) of the expander 4. On the other hand, water distributedto the second line connected to the passage P5 in the distribution valve106 becomes, by passing through a pressure reducing valve 107 disposedin the second line, a lower temperature, lower pressure steam than thehigh temperature, high pressure steam, and is supplied to a low pressuresection (vane chambers 75 of the expander 4, which will be describedlater) of the expander 4. In this way, since the heated water from thedistribution valve 106 is converted into steam by the pressure reducingvalve 107 and supplied to the low pressure section of the expander 4,the output of the expander 4 can be increased by utilizing effectivelythe thermal energy received by the water in the water jacket 105 of theinternal combustion engine 1. Water distributed to the third lineconnected to the passage P6 is supplied to a lubrication section of theexpander 4. Since the lubrication section of the expander 4 islubricated with high temperature water heated by the water jacket 105,it is possible to prevent the expander 4 from being overcooled, thusreducing any cooling loss. The decreased temperature, decreased pressurewater-containing steam discharged from the expander 4 is supplied to thecondenser 5, which is disposed in a passage P8, and carries out heatexchange with cooling air from a cooling fan 109 driven by an electricmotor 108, and condensed water thus formed is discharged into the tank6. Furthermore, water distributed to the fourth line, which is connectedto a plurality of passages P7, is supplied to auxiliary equipment 110such as a heater for warming a passenger compartment or a thermoelectricelement and releases the heat, and water having had its temperature thusdecreased is discharged into the tank 6 via a check valve 111 disposedin a passage P9.

The low pressure pump 7, the high pressure pump 8, the distributionvalve 106, and the electric motor 108 are controlled by an electroniccontrol unit 112 according to the operational state of the internalcombustion engine 1, the operational state of the expander 4, theoperational state of the auxiliary equipment 110, the temperature of thewater within the tank 6, etc.

As shown in FIG. 2 and FIG. 3, a casing 11 of the expander 4 is formedfrom first and second casing halves 12 and 13, which are made of metal.The first and second casing halves 12 and 13 are formed from main bodyportions 12 a and 13 a, which in cooperation form a rotor chamber 14,and circular flanges 12 b and 13 b, which are joined integrally to theouter peripheries of the main body portions 12 a and 13 a, and the twocircular flanges 12 b and 13 b are joined together via a metal gasket15. The outer face of the first casing half 12 is covered with a transitchamber outer wall 16 having a deep bowl shape, and a circular flange 16a, which is joined integrally to the outer periphery of the transitchamber outer wall 16, is superimposed on the left face of the circularflange 12 b of the first casing half 12.

The outer face of the second casing half 13 is covered with an exhaustchamber outer wall 17 for housing a magnet coupling (not illustrated)for transmitting the output of the expander 4 to the outside, and acircular flange 17 a, which is joined integrally to the outer peripheryof the exhaust chamber outer wall 17, is superimposed on the right faceof the circular flange 13 b of the second casing half 13. Theabove-mentioned four circular flanges 12 b, 13 b, 16 a, and 17 a aretightened together by means of a plurality of bolts 18 disposed in thecircumferential direction. A transit chamber 19 is defined between thetransit chamber outer wall 16 and the first casing half 12, and anexhaust chamber 20 is defined between the exhaust chamber outer wall 17and the second casing half 13. The exhaust chamber outer wall 17 isprovided with an outlet (not illustrated) for guiding the decreasedtemperature, decreased pressure steam that has finished work in theexpander 4 to the condenser 5.

The main body portions 12 a and 13 a of the two casing halves 12 and 13have hollow bearing tubes 12 c and 13 c projecting outward in thelateral direction, and a rotating shaft 21 having a hollow portion 21 ais rotatably supported by these hollow bearing tubes 12 c and 13 c via apair of bearing members 22 and 23. The axis L of the rotating shaft 21thus passes through the intersection of the major axis and the minoraxis of the rotor chamber 14, which has a substantially ellipticalshape.

A seal block 25 is housed within a lubricating water supply member 24screwed onto the right-hand end of the second casing half 13, andsecured by a nut 26. A small diameter portion 21 b at the right-hand endof the rotating shaft 21 is supported within the seal block 25, a pairof seals 27 are disposed between the seal block 25 and the smalldiameter portion 21 b, a pair of seals 28 are disposed between the sealblock 25 and the lubricating water supply member 24, and a seal 29 isdisposed between the lubricating water supply member 24 and the secondcasing half 13. A filter 30 is fitted in a recess formed in the outerperiphery of the hollow bearing tube 13 c of the second casing half 13,and is prevented from falling out by means of a filter cap 31 screwedinto the second casing half 13. A pair of seals 32 and 33 are providedbetween the filter cap 31 and the second casing half 13.

As is clear from FIG. 4 and FIG. 13, a circular rotor 41 is rotatablyhoused within the rotor chamber 14, which has a pseudo-elliptical shape.The rotor 41 is fitted onto and joined integrally to the outer peripheryof the rotating shaft 21, and the axis of the rotor 41 and the axis ofthe rotor chamber 14 coincide with the axis L of the rotating shaft 21.The shape of the rotor chamber 14 viewed in the axis L direction ispseudo-elliptical, and is similar to a rhombus with its four apexesrounded, the shape having a major axis DL and a minor axis DS. The shapeof the rotor 41 viewed in the axis L direction is a perfect circlehaving a diameter DR that is slightly smaller than the minor axis DS ofthe rotor chamber 14.

The cross-sectional shapes of the rotor chamber 14 and the rotor 41viewed in a direction orthogonal to the axis L are all racetrack-shaped.That is, the cross-sectional shape of the rotor chamber 14 is formedfrom a pair of flat faces 14 a extending parallel to each other at adistance d, and arc-shaped faces 14 b having a central angle of 180°that are smoothly connected to the outer peripheries of the flat faces14 a and, similarly, the cross-sectional shape of the rotor 41 is formedfrom a pair of flat faces 41 a extending parallel to each other at thedistance d, and arc-shaped faces 41 b having a central angle of 180°that are smoothly connected to the outer peripheries of the flat faces41 a. The flat faces 14 a of the rotor chamber 14 and the flat faces 41a of the rotor 41 are in contact with each other, and a pair ofcrescent-shaped spaces are formed between the inner peripheral face ofthe rotor chamber 14 and the outer peripheral face of the rotor 41 (seeFIG. 4).

The structure of the rotor 41 is now explained in detail with referenceto FIG. 3 to FIG. 6, and FIG. 11.

The rotor 41 is formed from a rotor core 42 that is formed integrallywith the outer periphery of the rotating shaft 21, and twelve rotorsegments 43 that are fixed so as to cover the periphery of the rotorcore 42 and form the outer shell of the rotor 41. Twelve ceramic (orcarbon) cylinders 44 are mounted radially in the rotor core 42 at 30°intervals and fastened by means of clips 45 to prevent them falling out.A small diameter portion 44 a is projectingly provided at the inner endof each of the cylinders 44, and a gap between the base end of the smalldiameter portion 44 a and a sleeve 84 is sealed via a C seal 46. Theextremity of the small diameter portion 44 a is fitted into the outerperipheral face of the sleeve 84, which is hollow, and a cylinder bore44 b communicates with first and second steam passages S1 and S2 withinthe rotating shaft 21 via twelve third steam passages S3 running throughthe small diameter portion 44 a and the rotating shaft 21. A ceramicpiston 47 is slidably fitted within each of the cylinders 44. When thepiston 47 moves to the radially innermost position, it retractscompletely within the cylinder bore 44 b, and when it moves to theradially outermost position, about half of the whole length projectsoutside the cylinder bore 44 b.

Each of the rotor segments 43 is a hollow wedge-shaped member having acentral angle of 30°, and has two recesses 43 a and 43 b formed on thefaces thereof that are opposite the pair of flat faces 14 a of the rotorchamber 14, the recesses 43 a and 43 b extending in an arc shape withthe axis L as the center, and lubricating water outlets 43 c and 43 dopen in the middle of the recesses 43 a and 43 b. Furthermore, fourlubricating water outlets 43 e and 43 f open on the end faces of therotor segments 43, that is, the faces that are opposite vanes 48, whichwill be described later.

The rotor 41 is assembled as follows. The twelve rotor segments 43 arefitted around the outer periphery of the rotor core 42, which ispreassembled with the cylinders 44, the clips 45, and the C seals 46,and the vanes 48 are fitted in twelve vane channels 49 formed betweenadjacent rotor segments 43. At this point, in order to form apredetermined clearance between the vanes 48 and the rotor segments 43,shims having a predetermined thickness are disposed on opposite faces ofthe vanes 48. In this state, the rotor segments 43 and the vanes 48 aretightened inward in the radial direction toward the rotor core 42 bymeans of a jig so as to precisely position the rotor segments 43relative to the rotor core 42, and each of the rotor segments 43 is thenprovisionally retained on the rotor core 42 by means of provisionalretention bolts 50 (see FIG. 8). Subsequently each of the rotor segments43 and the rotor core 42 are co-machined so as to make two knock pinholes 51 run therethrough, and four knock pins 52 are press-fitted inthe two knock pin holes 51 so as to join each of the rotor segments 43to the rotor core 42.

As is clear from FIG. 8, FIG. 9, and FIG. 12, a through hole 53 runningthrough the rotor segment 43 and the rotor core 42 is formed between thetwo knock pin holes 51, and recesses 54 are formed at opposite ends ofthe through hole 53. Two pipe members 55 and 56 are fitted within thethrough hole 53 via seals 57 to 60, and an orifice-forming plate 61 anda lubricating water distribution member 62 are fitted into each of therecesses 54 and secured by a nut 63. The orifice-forming plate 61 andthe lubricating water distribution member 62 are prevented from rotatingrelative to the rotor segments 43 by two knock pins 64 running throughknock pin holes 61 a of the orifice-forming plate 61 and fitted intoknock pin holes 62 a of the lubricating water distribution member 62,and a gap between the lubricating water distribution member 62 and thenut 63 is sealed by an O ring 65.

A small diameter portion 55 a formed in an outer end portion of one ofthe pipe members 55 communicates with a sixth water passage W6 withinthe pipe member 55 via a through hole 55 b, and the small diameterportion 55 a also communicates with a radial distribution channel 62 bformed on one side face of the lubricating water distribution member 62.The distribution channel 62 b of the lubricating water distributionmember 62 extends in six directions, and the extremities thereofcommunicate with six orifices 61 b, 61 c, and 61 d of theorifice-forming plate 61. The structures of the orifice-forming plate61, the lubricating water distribution member 62, and the nut 63provided at the outer end portion of the other pipe member 56 areidentical to the structures of the above-mentioned orifice-forming plate61, lubricating water distribution member 62, and nut 63.

Downstream sides of the two orifices 61 b of the orifice-forming plate61 communicate with the two lubricating water outlets 43 e, which openso as to be opposite the vane 48, via seventh water passages W7 formedwithin the rotor segments 43; downstream sides of the two orifices 61 ccommunicate with the two lubricating water outlets 43 f, which open soas to be opposite the vane 48, via eighth water passages W8 formedwithin the rotor segment 43; and downstream sides of the two orifices 61d communicate with the two lubricating water outlets 43 c and 43 d,which open so as to be opposite the rotor chamber 14, via ninth waterpassages W9 formed within the rotor segment 43.

As is clear from reference in addition to FIG. 5, an annular channel 67is defined by a pair of O rings 66 on the outer periphery of thecylinder 44, and the sixth water passage W6 formed within said one ofthe pipe members 55 communicates with the annular channel 67 via fourthrough holes 55 c running through the pipe member 55 and a tenth waterpassage W10 formed within the rotor core 42. The annular channel 67communicates with sliding surfaces of the cylinder bore 44 b and thepiston 47 via an orifice 44 c. The position of the orifice 44 c of thecylinder 44 is set so that it stays within the sliding surface of thepiston 47 when the piston 47 moves between top dead center and bottomdead center.

As is clear from FIG. 3 and FIG. 9, the first water passage W1 formed inthe lubricating water supply member 24 communicates with the smalldiameter portion 55 a of said one of the pipe members 55 via a secondwater passage W2 formed in the seal block 25, third water passages W3formed in the small diameter portion 21 b of the rotating shaft 21, anannular channel 68 a formed in the outer periphery of a water passageforming member 68 fitted in the center of the rotating shaft 21, afourth water passage W4 formed in the rotating shaft 21, a pipe member69 bridging the rotor core 42 and the rotor segments 43, and fifth waterpassages W5 formed so as to bypass the knock pin 52 on the radiallyinner side of the rotor segment 43.

As shown in FIG. 7, FIG. 9, and FIG. 11, twelve vane channels 49 areformed between adjacent rotor segments 43 of the rotor 41 so as toextend in the radial direction, and the plate-shaped vanes 48 areslidably fitted in the respective vane channels 49. Each of the vanes 48has a substantially U-shaped form comprising parallel faces 48 afollowing the parallel faces 14 a of the rotor chamber 14, an arc-shapedface 48 b following the arc-shaped face 14 b of the rotor chamber 14,and a notch 48 c positioned between the parallel faces 48 a. Rollers 71having a roller bearing structure are rotatably supported on a pair ofsupport shafts 48 d projecting from the parallel faces 48 a.

A U-shaped synthetic resin seal 72 is retained in the arc-shaped face 48b of the vane 48, and the extremity of the seal 72 projects slightlyfrom the arc-shaped face 48 b of the vane 48 and comes into slidingcontact with the arc-shaped face 14 b of the rotor chamber 14. Tworecesses 48 e are formed on each side of the vane 48, and these recesses48 e are opposite the two radially inner lubricating water outlets 43 ethat open on the end faces of the rotor segment 43. A plurality (5 inthe embodiment) of pockets 48 f are recessed in opposite sides of thevane 48 so as to extend radially (see FIG. 7). The positions of thepockets 48 f are set so that, when the vane 48 projects from the vanechannel 49 by only a predetermined distance, the radially outer ends ofthe pockets 48 f open within the rotor chamber 14. A piston receivingmember 73, which is provided so as to project radially inward in themiddle of the notch 48 c of the vane 48, abuts against the radiallyouter end of the piston 47.

As is clear from FIG. 4, two pseudo-elliptical annular channels 74having a similar shape to that of a rhombus with its four apexes roundedare provided in the flat faces 14 a of the rotor chamber 14 defined bythe first and second casing halves 12 and 13, and the pair of rollers 71of each of the vanes 48 are rollably engaged with these annular channels74. The distance between these annular channels 74 and the arc-shapedface 14 b of the rotor chamber 14 is constant throughout the wholecircumference. Therefore, when the rotor 41 rotates, the vane 48 havingthe rollers 71 guided by the annular channels 74 reciprocates radiallywithin the vane channel 49, and the seal 72 mounted on the arc-shapedface 48 b of the vane 48 slides along the arc-shaped face 14 b of therotor chamber 14 with a constant amount of compression. This enablesdirect physical contact between the rotor chamber 14 and the vanes 48 tobe prevented and vane chambers 75 defined between adjacent vanes 48 tobe reliably sealed while preventing any increase in the slidingresistance or the occurrence of wear.

As is clear from FIG. 2, a pair of circular seal channels 76 are formedin the flat faces 14 a of the rotor chamber 14 so as to surround theoutside of the annular channels 74. A pair of ring seals 79 equippedwith two O rings 77 and 78 are slidably fitted in the circular sealchannels 76, and the seal surfaces are opposite the recesses 43 a and 43b (see FIG. 4) formed in each of the rotor segments 43. The pair of ringseals 79 are prevented from rotating relative to the first and secondcasing halves 12 and 13 by knock pins 80.

As is clear from FIG. 2, FIG. 3, and FIG. 10, an opening 16 b is formedat the center of the transit chamber outer wall 16; a boss portion 81 aof a fixed shaft support member 81 disposed on the axis L is secured tothe inner face of the opening 16 b by a plurality of bolts 82, andsecured to the first casing half 12 by means of a nut 83. Acylinder-shaped ceramic sleeve 84 is fixed to the hollow portion 21 a ofthe rotating shaft 21. The outer peripheral face of the fixed shaft 85,which is integral with the fixed shaft support member 81, is relativelyrotatably fitted within the inner peripheral face of this sleeve 84. Agap between the left-hand end of the fixed shaft 85 and the first casinghalf 12 is sealed by a seal 86, and a gap between the right-hand end ofthe fixed shaft 85 and the rotating shaft 21 is sealed by a seal 87.

A steam supply pipe 88 is fitted into the fixed shaft support member 81,which is disposed on the axis L, and is secured by a nut 89, and theright-hand end of the steam supply pipe 88 is press-fitted into thecenter of the fixed shaft 85. The first steam passage S1, whichcommunicates with the steam supply pipe 88, is formed in the center ofthe fixed shaft 85 in the axial direction, and the pair of second steampassages S2 run radially through the fixed shaft 85 with a phasedifference of 180°. As described above, the twelve third steam passagesS3 run through the sleeve 84 and the small diameter portions 44 a of thetwelve cylinders 44 retained at intervals of 30° in the rotor 41 fixedto the rotating shaft 21, and radially inner end portions of these thirdsteam passages S3 are opposite the radially outer end portions of thesecond steam passages S2 so as to be able to communicate therewith.

A pair of notches 85 a are formed on the outer peripheral face of thefixed shaft 85 with a phase difference of 180°, and these notches 85 acan communicate with the third steam passages S3. The notches 85 a andthe transit chamber 19 communicate with each other via a pair of fourthsteam passages S4 formed axially in the fixed shaft 85, a fifth annularsteam passage S5 formed axially in the fixed shaft support member 81,and through holes 81 b opening on the outer periphery of the bossportion 81 a of the fixed shaft support member 81.

As shown in FIG. 2 and FIG. 4, a plurality of radially aligned intakeports 90 are formed in the first casing half 12 and the second casinghalf 13 at positions that are advanced by 15° in the direction ofrotation R of the rotor 41 relative to the minor axis of the rotorchamber 14. The interior space of the rotor chamber 14 communicates withthe transit chamber 19 by means of these intake ports 90. Furthermore, aplurality of exhaust ports 91 are formed in the second casing half 13 atpositions that are retarded by 15° to 75° in the direction of rotation Rof the rotor 41 relative to the minor axis of the rotor chamber 14. Theinterior space of the rotor chamber 14 communicates with the exhaustchamber 20 by means of these exhaust ports 91. These exhaust ports 91open in shallow depressions 13 d formed within the second casing half 13so that the seals 72 of the vanes 48 are not damaged by the edges of theexhaust ports 91.

The second steam passages S2 and the third steam passages S3, and thenotches 85 a of the fixed shaft 85 and the third steam passages S3, forma rotary valve V, which provides periodic communication therebetween byrotation of the rotating shaft 21 relative to the fixed shaft 85 (seeFIG. 10).

As is clear from FIG. 2, pressure chambers 92 are formed at the rearface of the ring seals 79 fitted in the circular seal channels 76 of thefirst and second casing halves 12 and 13. An eleventh water passage W11formed in the first and second casing halves 12 and 13 communicates withthe two pressure chambers 92 via a twelfth water passage W12 and athirteenth water passage W13, which are formed from pipes, and the ringseals 79 are urged toward the side face of the rotor 41 by virtue ofwater pressure applied to the two pressure chambers 92.

The eleventh water passage W11 communicates with the outer peripheralface of the annular filter 30 via a fourteenth water passage W14, whichis a pipe, and the inner peripheral face of the filter 30 communicateswith a sixteenth water passage W16 formed in the second casing half 13via a fifteenth water passage W15 formed in the second casing half 13.Water supplied to the sixteenth water passage W16 lubricates slidingsurfaces of the fixed shaft 85 and the sleeve 84. Water supplied to theouter periphery of the bearing member 23 from the inner peripheral faceof the filter 30 via a seventeenth water passage W17 lubricates theouter peripheral face of the rotating shaft 21 through an orificepenetrating the bearing members 23. On the other hand, water supplied tothe outer periphery of the bearing members 22 from the eleventh waterpassage W11 via an eighteenth water passage W18, which is a pipe,lubricates the outer peripheral face of the rotating shaft 21 through anorifice penetrating the bearing member 22, and then lubricates thesliding surfaces between the fixed shaft 85 and the sleeve 84.

Operation of the present embodiment having the above-mentionedarrangement is now explained.

Operation of the expander 4 is first explained. In FIG. 3, hightemperature, high pressure steam from the evaporator 3 is supplied tothe steam supply pipe 88, the first steam passage S1 passing through thecenter of the fixed shaft 85, and the pair of second steam passages S2passing radially through the fixed shaft 85. In FIG. 10, when the sleeve84 that rotates integrally with the rotor 41 and the rotating shaft 21in the direction shown by the arrow R reaches a predetermined phaserelative to the fixed shaft 85, the pair of third steam passages S3 thatare present on the advanced side in the direction of rotation R of therotor 41 relative to the position of the minor axis of the rotor chamber14 are made to communicate with the pair of second steam passages S2,and the high temperature, high pressure steam of the second steampassages S2 is supplied to the interiors of a pair of the cylinders 44via the third steam passages S3 and pushes the pistons 47 radiallyoutward. In FIG. 4, when the vanes 48 pushed by the pistons 47 moveradially outward, since the pair of rollers 71 provided on the vanes 48are engaged with the annular channels 74, the forward movement of thepistons 47 is converted into rotational movement of the rotor 41.

Even after the communication between the second steam passages S2 andthe third steam passages S3 is blocked as a result of the rotation ofthe rotor 41, the high temperature, high pressure steam within thecylinders 44 continues to expand, thus making the pistons 47 movefurther forward and thereby enabling the rotor 41 to continue to rotate.When the vanes 48 reach the position of the major axis of the rotorchamber 14, the third steam passages S3 communicating with thecorresponding cylinders 44 also communicate with the notches 85 a of thefixed shaft 85, the pistons 47 are pushed by the vanes 48 whose rollers71 are guided by the annular channels 74 and move radially inward, andthe steam within the cylinders 44 accordingly passes through the thirdsteam passages S3, the notches 85 a, the fourth passages S4, the fifthpassage S5, and the through holes 81 b, and is supplied to the transitchamber 19 as a first decreased temperature, decreased pressure steam.The first decreased temperature, decreased pressure steam is the hightemperature, high pressure steam that has been supplied from the steamsupply pipe 88, has finished the work of driving the pistons 47 and, asa result, has a decreased temperature and pressure. The thermal energyand the pressure energy of the first decreased temperature, decreasedpressure steam are lower than those of the high temperature, highpressure steam, but are still sufficient for driving the vanes 48.

The first decreased temperature, decreased pressure steam within thetransit chamber 19 is supplied to the vane chambers 75 within the rotorchamber 14 via the intake ports 90 of the first and second casing halves12 and 13, and further expands therein to push the vanes 48, thusrotating the rotor 41. A second decreased temperature, decreasedpressure steam that has finished work and accordingly has a furtherdecreased temperature and pressure is discharged from the exhaust ports91 of the second casing half 13 into the exhaust chamber 20, and issupplied therefrom to the condenser 5.

In this way, the expansion of the high temperature, high pressure steamenables the twelve pistons 47 to operate in turn to rotate the rotor 41via the rollers 71 and the annular channels 74, and the expansion of thefirst decreased temperature, decreased pressure steam, which is the hightemperature, high pressure steam whose temperature and pressure havedecreased, enables the rotor 41 to rotate via the vanes 48, therebyproviding an output from the rotating shaft 21.

Lubrication of the vanes 48 and the pistons 47 of the expander 4 withwater is now explained.

As water for lubricating each section of the expander 4, hightemperature water distributed to the passage P6 in the distributionvalve 106 after being heated by the water jacket 105 is used.

In FIG. 3 and FIG. 8, the water that has been supplied to the firstwater passage W1 of the lubricating water supply member 24 flows intothe small diameter portion 55 a of one of the pipe members 55 via thesecond water passages W2 of the seal block 25, the third water passagesW3 of the rotating shaft 21, the annular channel 68 a of the waterpassage forming member 68, the fourth water passage W4 of the rotatingshaft 21, and the fifth water passages W5 formed in the pipe member 69and the rotor segment 43, and the water that has flowed into the smalldiameter portion 55 a flows into the small diameter portion 56 a of theother pipe member 56 via the through hole 55 b of said one of the pipemembers 55, the sixth water passage W6 formed in the pipe members 55 and56, and the through hole 56 b formed in the other pipe member 56.

A portion of the water that has passed through the six orifices 61 b, 61c, and 61 d of the orifice-forming plate 61 from the small diameterportions 55 a and 56 a of the pipe members 55 and 56 via thedistribution channel 62 b of the lubricating water distribution member62 issues from the four lubricating water outlets 43 e and 43 f thatopen on the end faces of the rotor segment 43, and another portion ofthe water issues from the lubricating water outlets 43 c and 43 d withinthe arc-shaped recesses 43 a and 43 b formed on the side faces of therotor segment 43.

In this way, the water issuing from the lubricating water outlets 43 eand 43 f on the end faces of each of the rotor segments 43 into the vanechannel 49 supports the vane 48 in a floating state by forming ahydrostatic bearing between the vane channel 49 and the vane 48, whichis slidably fitted in the vane channel 49, thus preventing physicalcontact between the end face of the rotor segment 43 and the vane 48 andthereby preventing the occurrence of seizing and wear. Supplying thewater for lubricating the sliding surfaces of the vane 48 via the waterpassages provided in a radial shape within the rotor 41 in this way notonly enables the water to be pressurized by virtue of centrifugal forcebut also enables the temperature of the periphery of the rotor 41 to bestabilized, thus lessening the effect of thermal expansion and therebyminimizing the leakage of steam by maintaining a preset clearance.

Since water is retained in the recesses 48 e, two of which are formed oneach of the opposite faces of the vane 48, these recesses 48 e functionas pressure reservoirs, thereby suppressing any decrease in pressure dueto leakage of water. As a result the vane 48, which is held between theend faces of the pair of rotor segments 43, is in a floating state dueto the water, and the sliding resistance can thereby be reducedeffectively. Furthermore, when the vane 48 reciprocates, the radialposition of the vane 48 relative to the rotor 41 changes, and since therecesses 48 e are provided not on the rotor segment 43 side but on thevane 48 side and in the vicinity of the rollers 71, where the largestload is imposed on the vane 48, the reciprocating vane 48 can always bekept in a floating state, and the sliding resistance can thereby bereduced effectively.

A portion of high pressure water supporting the vane 48 in a floatingstate is retained in the five pockets 48 f formed on each of theopposite sides of the vane 48; as shown in FIG. 16, when the vane 48projects by only a predetermined distance into the rotor chamber 14during an expansion stroke accompanying rotation of the rotor 41, thepockets 48 f open in the vane chamber 75 of the rotor chamber 14, andthe high pressure water retained in the pockets 48 f is supplied to thevane chamber 75, which has a lower pressure than that of the water. Inthis process, since the water supplied to the vane chamber 75 has passedthrough the water jacket 105 of the internal combustion engine 1 and ispreheated, it easily gasifies in the vane chamber 75 and becomes steam,and driving the vane 48 by the pressure energy of this steam enables theoutput of the expander 4 to be increased.

Graphs in FIG. 14 and FIG. 15 show states with certain specific factorsfor the expander 4 and certain specific steam conditions, steam beingthe gas-phase working medium, although the states vary quantitativelydepending on the factors, the conditions, etc.

The abscissa of the graph of FIG. 14 denotes the timing (phase) withwhich water is supplied to the vane chamber 75, and the ordinate thereofdenotes the amount of increase in output of the expander 4. The pressureof the water supplied to the vane chamber 75 via the sliding surfaces is2 MPa, and the ratio of the amount of water supplied to the vane chamber75 via the sliding surfaces relative to the amount of water suppliedfrom the evaporator 3 to the vane chamber 75 of the expander 4 via thepassage P4 is 60%. FIG. 14 shows cases in which temperature of the watersupplied to the vane chamber 75 via the sliding surfaces is 50° C., 100°C, and 200° C., and it can be seen that the higher the temperature ofthe water, the larger the amount of increase in the output of theexpander 4, and the more advanced the phase at which the amount ofincrease in the output is a maximum.

The abscissa and the ordinate of the graph of FIG. 15 are the same asthose of the graph of FIG. 14, and cases in which the ratio of theamount of water supplied to the vane chamber 75 via the sliding surfacesrelative to the amount of water supplied from the evaporator 3 to thevane chamber 75 of the expander 4 via the passage P4 is 0%, 20%, 40%,and 60% are shown. The pressure of the water supplied to the vanechamber 75 via the sliding surfaces is 2 MPa, and the temperaturethereof is a constant value of 200° C. It can be seen that when theratio of the amount of water supplied to the vane chamber 75 via thesliding surfaces increases, although the amount of increase in theoutput of the expander 4 increases, the phase at which the amount ofincrease in the output is a maximum is constant and does not vary.

In this way, by supplying a portion of high temperature lubricatingwater with a predetermined timing to the vane chambers 75, which are onan expansion stroke accompanying reciprocation of the vane 48, theoutput of the expander 4 can be increased by converting effectively thethermal energy of the lubricating water into rotational energy of therotor 41 without wastefully disposing of the thermal energy. Theposition of the pockets 48 f of the vane 48, that is, the timing withwhich water is supplied from the pockets 48 f to the vane chambers 75,is determined so that the amount of increase in the output of theexpander 4 becomes a maximum, with the prerequisite that the pressure ofthe lubricating water is higher than the pressure of the vane chambers75. If the temperature of the lubricating water is too high there is apossibility that the lubricating water might gasify before it issupplied to the vane chambers 75, thus degrading the function of thehydrostatic bearing, whereas in contrast if the temperature of thelubricating water is too low there is a possibility that the lubricatingwater supplied to the vane chambers 75 might not gasify and notcontribute to an increase in the output of the expander 4. Thetemperature of the lubricating water is therefore set while taking thesesituations into consideration.

The amount of water supplied to the vane chambers 75 from the pockets 48f can be freely adjusted by changing the number and the capacity of thepockets 48 f.

In FIG. 2, by supplying water into the pressure chambers 92 at thebottom portions of the circular seal channels 76 of the first casinghalf 12 and the second casing half 13 so as to urge the ring seals 79toward the side faces of the rotor 41, and making the water issue fromthe lubricating water outlets 43 c and 43 d formed within the recesses43 a and 43 b of each of the rotor segments 43 so as to form ahydrostatic bearing on the sliding surfaces with the flat faces 14 a ofthe rotor chamber 14, the flat faces 41 a of the rotor 41 can be sealedby the ring seals 79 that are in a floating state within the circularseal channels 76 and, as a result, the steam within the rotor chamber 14can be prevented from leaking through a gap with the rotor 41. In thisprocess, the ring seals 79 and the rotor 41 are isolated from each otherby a film of water supplied from the lubricating water outlets 43 c and43 d and do not make physical contact with each other, and even if therotor 41 tilts, tilting of the ring seals 79 within the circular sealchannels 76 so as to track the tilting of the rotor 41 enables stablesealing characteristics to be maintained while minimizing the frictionalforce.

The water that has lubricated the sliding section between the ring seals79 and the rotor 41 is supplied to the rotor chamber 14 by virtue ofcentrifugal force, and discharged therefrom to the exterior of thecasing 11 via the exhaust ports 91.

Furthermore, in FIG. 5, water that has been supplied from the sixthwater passage W6 within the pipe member 55 to the sliding surfacesbetween the cylinder 44 and the piston 47 via the tenth water passageW10 within the rotor segments 43 and the annular channel 67 of the outerperiphery of the cylinder 44 exhibits a sealing function by virtue ofthe viscous properties of the film of water formed on the slidingsurfaces, thereby preventing effectively the high temperature, highpressure steam supplied to the cylinder 44 from leaking past the slidingsurfaces with the piston 47. Since the water that is supplied to thesliding surfaces between the cylinder 44 and the piston 47 through theinterior of the expander 4, which is in a high temperature state, isheated, it is possible to minimize any decrease in output of theexpander 4 that might be caused by this water cooling the hightemperature, high pressure steam supplied to the cylinder 44.

Furthermore, the first water passage W1 and the eleventh water passageW11 are independent from each other, and water is supplied at a pressurethat is required for each of the lubrication sections. Morespecifically, the water that is supplied from the first water passage W1is mainly for floatingly supporting the vanes 48 and the rotor 41 bymeans of a hydrostatic bearing as described above, and it is required tohave a high pressure that can counterbalance variations in the load. Incontrast, the water that is supplied from the eleventh water passage W11mainly lubricates the surroundings of the fixed shaft 85, and since itis for sealing the high temperature, high pressure steam that leaks fromthe third steam passages S3 past the outer periphery of the fixed shaft85 so as to reduce the influence of thermal expansion of the fixed shaft85, the rotating shaft 21, the rotor 41, etc., it is only required tohave a pressure that is at least higher than the pressure of the transitchamber 19.

Since there are provided in this way two water supply lines, that is,the first water passage W1 for supplying high pressure water and theeleventh water passage W11 for supplying lower pressure water, problemscaused when only one water supply line for supplying high pressure wateris provided can be eliminated. That is, the problem of water havingexcess pressure being supplied to the surroundings of the fixed shaft85, thus increasing the amount of water flowing into the transit chamber19, and the problem of the fixed shaft 85, the rotating shaft 21, therotor 41, etc. being overcooled, thus decreasing the temperature of thesteam, can be prevented, and as a result the output of the expander 4can be increased while reducing the amount of water supplied.

Furthermore, since the water retained in the pockets 48 f is a portionof the high pressure water that is supplied from the first water passageW1 so as to hydrostatically support the vanes 48 and the rotor 41 in afloating state and to counterbalance variations in the load, highpressure water can be supplied to the pockets 48 f without requiring aspecial pump.

Moreover, since water, which is the same substance as steam, is used asa medium for sealing, there will be no problem even if the steam iscontaminated with water. If the sliding surfaces of the cylinder 44 andthe piston 47 were sealed by an oil, since it would be impossible toprevent the oil from contaminating the water or the steam, a specialfilter device for separating the oil would be required. Furthermore,since a portion of the water for lubricating the sliding surfaces of thevane 48 and the vane channels 49 is separated for sealing the slidingsurfaces of the cylinder 44 and the piston 47, it is unnecessary tospecially provide an extra water passage for guiding the water to thesliding surfaces, thus simplifying the structure.

Operation of the cooling system of the internal combustion engine 1including the waste heat recovery system 2 is explained with referencemainly to FIG. 1 and FIG. 2.

Water that is pumped from the tank 6 by the low pressure pump 7 issupplied via the passage P1 to the heat exchanger 102 provided in theexhaust pipe 101, preheated there, and then supplied to the water jacket105 of the internal combustion engine 1 via the passage P2. Water thatflows through the interior of the water jacket 105 cools the cylinderblock 103 and the cylinder head 104, which are heated sections of theinternal combustion engine 1, and is supplied to the distribution valve106 in an increased temperature state. Since water preheated by the heatexchanger 102 of the exhaust pipe 101 is thus supplied to the waterjacket 105, when the internal combustion engine 1 is cold its warming-upcan be accelerated, and it is also possible to improve the performanceof the evaporator 3 by preventing overcooling of the internal combustionengine 1 and increasing the temperature of the exhaust gas.

A portion of the high temperature water distributed in the distributionvalve 106 is pressurized by the high pressure pump 8 disposed in thepassage P4, supplied to the evaporator 3, carries out heat exchangethere with the exhaust gas, and becomes high temperature, high pressuresteam. The high temperature, high pressure steam thus generated in theevaporator 3 is supplied to the steam supply pipe 88 of the expander 4,passes through the cylinders 44 and the vane chambers 75, and isdischarged into the condenser 5 after driving the rotating shaft 21.

Another portion of the high temperature water distributed in thedistribution valve 106 is depressurized by the pressure reducing valve107 disposed in the passage P5 and becomes steam, which is then suppliedto the transit chamber 19 of the expander 4. The steam supplied to thetransit chamber 19 is combined with the first decreased temperature,decreased pressure steam that has been supplied from the steam supplypipe 88 and has passed through the cylinders 44, the combined steam thenbeing discharged into the condenser 5 after driving the rotating shaft21. In this way, since a portion of the high temperature water from thedistribution valve 106 is turned into steam in the pressure reducingvalve 107 and supplied to the expander 4, the output of the expander 4can be increased by utilizing effectively the thermal energy that isreceived by the water in the water jacket 105 of the internal combustionengine 1. Moreover, another portion of the high temperature waterdistributed in the distribution valve 106 is supplied to the first waterpassage W1 of the expander 4 via the passage P6, and lubricates each ofthe sections that are to be lubricated. In this way, since thelubrication sections of the expander 4 are lubricated using hightemperature water, it is possible to prevent the expander 4 from beingovercooled, thus reducing any cooling loss. Furthermore, water that hasentered the vane chambers 75 during the expansion stroke afterlubrication is mixed with the steam of the vane chambers 75, heated, andturns into steam, and the resulting expansion increases the output ofthe expander 4. The second decreased temperature, decreased pressuresteam that has been discharged from the expander 4 into the passage P8is supplied to the condenser 5, is cooled there by the cooling fan 109,becomes water, and is returned to the tank 6. Moreover, another portionof the high temperature water distributed in the distribution valve 106carries out heat exchange with the auxiliary equipment 110 disposed inthe passage P7, is thus cooled, and is then returned to the tank 6 viathe check valve 111.

As hereinbefore described, since a water circulation route in whichwater pumped from the tank 6 by the low pressure pump 7 is supplied tothe water jacket 105 so as to cool the heated sections of the internalcombustion engine 1, is then supplied to the auxiliary equipment 110 andcooled there, and is returned to the tank 6 is combined with a watercirculation route of the waste heat recovery system 2 in which a portionof the water discharged from the water jacket 105 is distributed as aworking medium and this water is returned to the tank 6 via the highpressure pump 8, the evaporator 3, the expander 4, and the condenser 5,and since the water circulation route of the cooling system for theinternal combustion engine 1 that passes through the water jacket 105and the auxiliary equipment 110 is made to have a low pressure and alarge flow rate, and the water circulation route of the waste heatrecovery system 2 is made to have a high pressure and a small flow rate,it is possible to supply water to the cooling system of the internalcombustion engine 1 and the waste heat recovery system 2 at anappropriate flow rate and an appropriate pressure, and it is alsopossible to eliminate the need for a radiator by sufficiently coolingthe heated sections of the internal combustion engine 1 whilemaintaining the performance of the waste heat recovery system 2.Moreover, since the water supplied from the low pressure pump 7 to thewater jacket 105 is preheated by the heat exchanger 102 provided in theexhaust pipe 101, waste heat of the internal combustion engine 1 can beutilized more effectively.

Furthermore, since the heat exchanger 102 to which low temperature wateris supplied from the low pressure pump 7 is provided in the exhaust pipe101 downstream of the evaporator 3 at a position where the temperatureof the exhaust gas is lower, surplus waste heat of the exhaust gas canbe completely recovered efficiently. Moreover, since water preheated bythe heat exchanger 102 is supplied to the water jacket 105, it ispossible to prevent the internal combustion engine 1 from beingovercooled, increase the heat of combustion, that is, the thermal energyof the exhaust gas, by further increasing the temperature of the exhaustgas, and improve the waste heat recovery efficiency.

A second embodiment of the present invention is now explained withreference to FIG. 17.

In this embodiment, a U-shaped lubricating water guide channel 43 g isformed on an end face of a rotor segment 43 opposite a vane 48 so as toextend along an arc-shaped face 41 b and a pair of flat faces 41 a of arotor 41. Opposite ends of the lubricating water guide channel 43 gcommunicate, via a clearance between the flat faces 41 a of the rotor 41and flat faces 14 a of a rotor chamber 14, with annular channels 74 forguiding rollers 71. Pockets 48 f formed on the surface of the vane 48communicate with the lubricating water guide channel 43 g of the rotorsegment 43, and the pockets 48 f are replenished with high pressurewater from the lubricating water guide channel 43 g.

Water that has lubricated sliding surfaces of the end face of the rotorsegment 43 and the vane 48 moves radially outward by virtue ofcentrifugal force, and the majority of the water is captured by theU-shaped lubricating water guide channel 43 g formed in the rotorsegment 43 and then discharged into the annular channels 74, which areat low pressure and with which the opposite ends of the lubricatingwater guide channel 43 g communicate. When the pockets 48 f which arereplenished with high pressure water from the lubricating water guidechannel 43 g open in the vane chamber 75 accompanying radially outwardmovement of the vane 48, water supplied from the pockets 48 f to thevane chamber 75 gasifies and becomes steam, and the steam pushes thevane 48 so as to increase the output of the expander 4.

In this way, since the lubricating water guide channel 43 g preventsunrestricted flow into the rotor chamber 14 of water that has been usedin a hydrostatic bearing for supporting the vane 48 in a floating state,it is possible to supply an appropriate amount of water with anappropriate timing to the vane chambers 75 while preventing the outputof the expander 4 from being reduced by a large amount of water coolingthe steam within the vane chambers 75, which are defined by the rotorchamber 14, thereby increasing the output of the expander 4 effectively.

In the first embodiment, the pressure of the water retained in thepockets 48 f is equal to the pressure of the lubricating water supplied,but in the second embodiment, the pressure of the water retained in thepockets 48 f is equal to the pressure of the lubricating water guidechannel 43 g, and the pressure of the lubricating water guide channel 43g is equal to the pressure of the annular channels 74, with which thelubricating water guide channel 43 g communicates. Therefore, by settingthe pressure of the annular channels 74 higher than the pressure of thevane chamber 75 that is at a given position, water can be suppliedwithout problem from the pockets 48 f to the vane chamber 75 that is atthe given position.

A third embodiment of the present invention is now explained withreference to FIG. 18.

The third embodiment is a modification of the second embodiment; whereasthe pockets 48 f of the second embodiment have the main function ofretaining water, slits 48 g of the third embodiment, which correspond tothe pockets 48 f of the second embodiment, have the main functions ofmaking a lubricating water guide channel 43 g communicate with a vanechamber 75, and supplying water captured in the lubricating water guidechannel 43 g to the vane chamber 75 via the slits 48 g. This enables theamount of water supplied to the vane chamber 75 to be set without therebeing too much or too little, while making machining easy compared withthat for the pockets 48 f, without increasing the number or the volumeof the slits 48 g.

The timing with which the slits 48 g communicate with the vane chamber75 and with which the supply of water is started is the same as that ofthe second embodiment, and is when the vane 48 moves radially outwardand the radially outer ends of the slits 48 g open in the vane chamber75. The timing with which the supply of water to the vane chamber 75 iscompleted is when the vane 48 moves radially further outward andcommunication of the radially inner ends of the slits 48 g with thelubricating water guide channel 43 g is blocked. Therefore, by changingthe positions of the radially inner ends of the slits 48 g, the timingwith which the supply of water to the vane chamber 75 is completed, thatis, the amount of water supplied to the vane chamber 75, can be setfreely. Furthermore, during an exhaust stroke, water that resides inannular channels 74 for guiding rollers 71 can be discharged from thelubricating water guide channel 43 g to the vane chamber 75 via theslits 48 g.

Other than the embodiments described above, as an arrangement for apower conversion device for converting the forward movement of pistons47 into the rotational movement of a rotor 41, the forward movement ofthe pistons 47 can be directly transmitted to rollers 71 withoutinvolving vanes 48, and can be converted into rotational movement byengagement with annular channels 74. Furthermore, as long as the vanes48 are always spaced from the inner peripheral face of a rotor chamber14 by a substantially constant gap as a result of cooperation betweenthe rollers 71 and the annular channels 74 as described above, thepistons 47 and the rollers 71, and also the vanes 48 and the rollers 71,can independently work together with the annular channels 74.

When the expander 4 is used as a compressor, the rotor 41 is rotated bythe rotating shaft 21 in a direction opposite to the arrow R in FIG. 4,outside air is drawn in by the vanes 48 from the exhaust ports 91 intothe rotor chamber 14 and compressed, and the low pressure compressed airthus obtained is drawn in from the intake ports 90 into the cylinders 44via the transit chamber 19, the through holes 81 b, the fifth steampassages S5, the fourth steam passages S4, the notches 85 a of the fixedshaft 85 and the third steam passages S3, and compressed there by thepistons 47 to give high pressure compressed air. The high pressurecompressed air thus obtained is discharged from the cylinders 44 via thethird steam passages S3, the second steam passages S2, the first steampassage S1, and the steam supply pipe 88. When the expander 4 is used asa compressor, the steam passages S1 to S5 and the steam supply pipe 88are read instead as air passages S1 to S5 and air supply pipe 88.

Although embodiments of the present invention are described in detailabove, the present invention can be modified in a variety of wayswithout departing from the scope and spirit thereof.

For example, in the embodiments, the expander 4 is illustrated as therotary fluid machine, but the present invention can also be applied to acompressor.

Furthermore, in the embodiments, steam and water are used as thegas-phase working medium and the liquid-phase working medium, but otherappropriate working media can also be employed.

INDUSTRIAL APPLICABILITY

The present invention can desirably be applied to an expander employingsteam (water) as a working medium, but can also be applied to anexpander employing any other working medium and a compressor employingany working medium.

1. A rotary fluid machine comprising a rotor chamber (14) formed in acasing (11), a rotor (41) rotatably housed within the rotor chamber(14), a plurality of vane channels (49) formed radially in the rotor(41), and a plurality of vanes (48) slidably supported in the respectivevane channels (49); the vanes (48) being supported in a floating stateby a hydrostatic bearing formed by supplying a liquid-phase workingmedium to sliding surfaces of the vane channels (49) and the vanes (48),and the rotary fluid machine interconverting the rotational energy ofthe rotor (41) and the pressure energy of a gas-phase working mediumsupplied to vane chambers (75) defined by the rotor (41), the casing(11), and the vanes (48); wherein liquid-phase working medium guidemeans for introducing into the vane chambers (75) the liquid-phaseworking medium for the hydrostatic bearing is provided on slidingsurfaces of the vanes (48), and the temperature and the pressure of theliquid-phase working medium that is introduced into the vane chambers(75) by the liquid-phase working medium guide means are set so that theliquid-phase working medium can gasify into the gas-phase working mediumin the vane chambers (75).
 2. The rotary fluid machine according toclaim 1, wherein the liquid-phase working medium guide means comprises apocket (48 f) that is recessed in the sliding surface of the vane (48)so that it can retain the liquid-phase working medium, and when thepocket (48 f) communicates with the vane chamber (75) as a result ofradially outward movement of the vane (48) accompanying rotation of therotor (41), the liquid-phase working medium, which has a higher pressurethan the internal pressure of the vane chamber (75), is introduced intothe vane chamber (75):
 3. The rotary fluid machine according to eitherclaim 1 or claim 2, wherein the liquid-phase working medium for thehydrostatic bearing is preheated so that it gasifies when introducedinto the vane chamber (75).
 4. The rotary fluid machine according toclaim 3, wherein the liquid-phase working medium for the hydrostaticbearing is preheated by utilizing the waste heat of an internalcombustion engine (1).